Keeway RKS 125 STD running issues.

[Paincraft]

Hi all any help would be appreciated. 

 

Just  bought a 2019 2nd hand bike and apart from this particular issue it is very well maintained. Passed it MOT just before I bought it. My issue is this when starting it will run for a few minutes at idling and then will cut out, I can restart right away but this doesn't happen every time and it doesn't seem to matter if it is starting from cold or if the engine was warmed up. 

 

Something else happens but I don't know if this is related, when first starting, when I first get underway the throttle doesn't seem to be as smooth (seems to be a little bit jittery as if its missing) don't know if it is because I am not waiting for the engine to warm enough, but haven't had to wait this long on my previous bikes. Once it has been running for a few mins this seems to disappear and the throttle becomes smooth

 

Lastly wanted to ask if any one knows if the Chinese, Taiwanese and Korean 125 cc Motorcycles Haynes Manual covers the Keeway RKS 125 STD.

 

Thank you in advance 

[Mississippi Bullfrog]

Sounds like it's just cold starting issues. Check the usual service items and maybe give the lead and plug a spray of WD40 in case there's a touch of damp in them.

[Paincraft]

Will try that and see if it makes a difference, if anyone else has any ideas I would be grateful.

[Paincraft]

Checked the spark plug (which looks new) and lead but no issues at the same time I took the air filter out to check that and that was so clean, as if it was very new. While I was checking the air filter I noted a tube from the bottom of the tank, being quite new to my own maintenance on my motorbikes I didn't know what this was. It is quite long I don't know if it is supposed to be very long but when I removed it from where It was tucked in to the side of the bike water came out. After a bit of reading I found this was more than likely the vent hose, which if becomes blocked can cause the symptoms I have been having including one symptom I didn't mention in my first post which was a rush air as if the tank had become pressurised when opening  the fuel cap. Can't say if this is definitely the issue so will have to keep an eye on it.

 

[Mississippi Bullfrog]

On some bikes you need to purge the vent hose at regular service intervals. If you're hearing a rush of air it sounds like the tank isn't venting which will cause fuel issues.  

[Paincraft]

So thought this had sorted it when I started today I had no problems. On my way to work stopped to pick something up for a few minutes and when I returned and tried to start my engine it started ok but after a few secs the engine cut out, I restarted straight away but same thing happened; I noted that the revs remained low and then cut out completely. When I started again I kept the revs up for a minute or 2 and when I let it idle it was back at idling at normal level

 

Anything else I can try or look at?

[Paincraft]

Just as a visual this is what happens when it is warm and I have stopped the engine, I had just got home pick something from inside the house and came straight back to start the bike. You may see the fuel gauge flashing at the start I had plenty of fuel just takes a min to register how much when starting some times. Don't think that has anything to do with the problem.

https://youtu.be/RExR4jgzEsc